Abrasive machine.



G. T. JOHNSON.

ABRASIVE MACHINE.

APPLICATION FILED APR. 2 3. 1911.

Patented Dec. 24, 1918.

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I APPLICATION FILED APR. 23, I917. LQSEBQ, Patented Dec. 24,1918.

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G. T. JOHNSON.

ABRASIVE MACHINE.

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m: mum; runs cu. mwmumm mummam a g GUSTAVE T. JOHNSON, 0F BELOIT, WISCONSIN, ASSIGNOR TO P. B. YATES MACHINE COMPANY, OF BELOIT, WISCONSIN, A CORPORATION OF WISCONSIN.

ABRASIVE MACHINE.

Specification of Letters Patent. Patented Dec, 24, 1918,

Application filed April 23, 1917. Serial No. 163,846.

To all whom it may concern:

Be it lmown that I, GUSTAVE T. JOHNSON, a subject of the King of Sweden, residing at Beloit, in the county of Rock and State of Wisconsin, have invented certain new and useful Improvements in Abrasive Machines, of which the following is a specification.

In abrasive machines, such as those using endless sand belts for the smoothing or polishing of lumber, paper or cloth belts suitably surfaced with the abradant are ordinarily employed. Cloth belts of this character are rather expensive, although they perform their functions satisfactorily, whereas the cheaper paper belts of this kind wear out rather quickly by reason of tearing under the strains imposed upon them.

One of the leading objects of the present invention is the provision of a'simple, improved construction of this general type, which will permit the employment of the less expensive weaker paper or similar belt to a better advantage, overcomlng the de-' fects in the prior mechanisms which subjected them to destructive strains.

In the new device, two separate lndepend ent belts are employed, the one a backing or cushion belt, and the other an abradant belt inclosing and co-acting with the backing belt. In the operation of these superposed, cooperating belts, both of which co-act with a suitable abutment or pressure-wall, the strain is largely, if not entirely, taken off of the outer sand-belt, and, when it becomes worn out, it can be readily replaced, whereas the backing belt is subjected to practically no wear, and can be used indefinitely. Stated somewhat differently, the relatively-strong, driving backing belt is provided with an easily-replaced, abradant surfacing, which travels with it, but nevertheless is not adhered to it.

Inasmuch as the two belts are likely to stretch unequally, each is supplied with its own independent tension appliance, and since the two are likely to require adjustment to obtain proper tracking or travel, they are equipped with separate means to effect these results.

Various minor features of advantage, novelty, and improvement in the invention will be appreciated by those skilled in this art from a consideration of the structural characteristics and modes of operation of the preferred embodiments of the invention described in detail below, and illustrated fully in the accompanying drawings forming a part of this specification, and throughout the various views of which like reference characters refer to the same parts.

In the drawings:

Figure 1 is a plan view of the improved structure;

Fig. 2 is an elevation of the same;

Figs. 3, 4, and 5 are details of the mountings for the belt-tightening pulley of the sand-belt; Fig. 3 being a plan view with parts broken away, Fig. 4 an elevation, and Fig. 5 an end view;

Fig. 6 is a fragmentary plan of a portion of the structure equipped with a stationary form around which the abrasive belt passes instead of the pulley or roller as shown in Figs. 1 and 2, and includes also the adjustable pulley for tensioning the drive or back ing belt; and

Fig. 7 is an elevation of the same.

Referring to the drawings, it will be observed that the appliance includes a mainframe 10, a vertically-adjustable work-table 11, (the adjustment means being wellknown, and consequently not illustrated), and a stationary, upright, pressure-wall or abutment 12 extended substantially the full length of the table and maintained in position by brackets 13 and 14 mounted on the main-frame. At one end of the machine, I provide a horizontal, power-driven pulley 15, mounted on a vertical shaft 16 revoluble in suitable bearings, and rotated by any approved means.

At the opposite end of the machine, an upright-plate 17 (Figs. 6 and 7), having at its upper and lower ends arms 18 and 19 with bearings 20 and 21 for the shaft 22 of a roller or pulley 23, is angularly adjustably mounted on the pressure or abutment wall 12 by means of a pair of screws 24 engaging threaded openings in the wall and extended through slots 25 in the plate. I

In order to facilitate the tension adjustment and shifting of the roller or pulley 23 to obtain the proper tracking or travel of an endless backing or drive belt 26 of leather, rubber, fabric, steel, or other desirable material passing around the pulley 23 and the drive-pulley 15, and traveling along the front face of the abutment or pressure-wall 12 toward the work-table, the plate 17 is equipped at its top with a handle 27 and at about its middle with a lug 28 against which bears the end of a regulating screw 29 in a threaded hole in bracket 14. ()bviously, by loosening the screws 24, the roller or pulley 23, by means of handle 27, may be tilted slightly to secure the proper'and desired travel of the belt, it being practically impos-' sible to make both edges of the belt of exactly the same length. It is to compensate for this difference and thus cause the belt to run true, that the angular adjustment of the roller is needed or desirable. After the adjustment, the screws are, of course, again set up to maintain the plate and its pulley or roller in the new position. In case it is desired to tighten or tension the belt, as a whole, it may be readily effected by manipulation of screw 29, the screws 24 having been first loosened and later tightened.

The endless sand or abradant belt 30 overlies or incloses the backing, cushion, or drive belt in front of the wall 12, and passes around the pulley 15-with which it cooperates, over belt 26, around an adjustable tension pulley or roller 31. and another pulley or roller 32 at one end of the machine.

The pulley or'roller 31 may be adjusted to take up slack in the sand belt and to cause a proper tracking of the belt. Such roller or pulley is mounted on an apertured arm 33, furcrumed on the machine frame at 34. Adjustment of the position of this arm, and, consequently, the position of the roller, is obtained by means of a screw-threaded rod 35 extended through the aperture and provided with a collar '36 fixed to its end, between which and a plate 37 pressing against the arm, is provided a coil-spring 38, permitting a limited cushioned play or movement of the arm and roller. The threaded part of the rod has a cylindrical nut 39 with a handwheel or turning portion 40, the former resting in an upright, swiveled socket 41 mounted on a supporting-arm 42 outstanding from the machine-frame. Obviously, by turning nut 39 by hand-wheel 40, the position of the arm and roller may be varied and the sandbelt tightened or loosened, as may be required.

The free end of arm 33 terminates in an enlargement or lateral plate portion 43 on which is fulcrumed on a screw at 44 a bracket-member 45 provided with an apertured extension 46 accommodating an upright fixed shaft 47 on which the roller or pulley 41 is mounted for rotation. Element 42 has a downwardly-extended, apertured or slotted ear 48 receiving a rod 49 provided with a turning handle 50 on one side of the ear and a collar 51 fixed thereto on the opposite side of the ear, a portionof the rod being screw-threaded and taking into the depending threaded lug 52 on member 45. As will be readily understood, the turning of handle 50 causes a tilting of the roller or pulley 31, as shown in dotted lines in Fig. 5, whereby the abradant-belt may be caused to track or travel correctly, that is, make both edges equally taut. The part 45 is slotted at 53 concentrically with the pivot-screw 44 and receives a clamping or tightening screw 54 threaded into the member 43 and having a turning-handle 55. By rotating or loosening the screw the plate 45 carrying the pulley may be rendered subject to angular adjustment by screw 49, whereas tightening the screw securely fastens the parts rigidly together. v

In smoothing appliances of this charac ter, it is customary to provide for vibrating the abradant element to eliminate or avoid marks on the surface of the work. This machine is intended and designed to have such a vibratory means, but inasmuch as it forms no part of the present invention, it has not been illustrated.

The machine having been set in operation 7 so that the power pulley 15 drives the two superposed, cooperating belts, the Work resting on the table 11, is moved up against such duplex belt traveling lengthwise the table, in front of the abutment or pressure wall 12, the abradant belt being outermost and acting to perform'the usual smoothing or polishing function. The two belts are pressed together more or less by the work and the inner stronger one'sustains practically all of the strain, the outer one acting as a readily-detachable abradant facing which can be easily replaced when Worn out. As has been explained above, the belts have separate and independent means for maintaining them under suitable tension and for causing them to track or travelcorrectly.

Around or adjacent to the roller or pulley 32, I provide a curved, work-supporting table 60 so that the sand-paper belt which encircles the pulley 32 may be used for smoothing purposes, and, if, desired, may be so employed at the same time that other work is finished or smoothed on the table 11. At times it may be desirable to substitute for the rotatable pulley 32 a fixed or stationary form around which the sand-belt may pass, thus giving to such belt at that point a desired conformation adapted to perform the required smoothing function on a piece of work of like shape. Such a Structure is shown in Figs. 6 and 7, "wherein on r the fixed shaft 70, inserted after pulley 32' and its shaft has been removed, by means of set-screws 71, 71, I stationarily mount a form 72 of any desired shape, the form-being preferably faced with linoleum or sheet tin 73. Obviously, the work resting on table 60 may be brought against the sand-paper as it passes around the form, and smoothed and polished in the usual manner. .Such operation does not interfere with the belt performing its usual function with work on table 11 and the two operations may be carried on at the same time, if desired.

To those skilled in this art, it will be apparent and appreciated that many minor mechanical changes may be made in the structure set forth herein Without departure from the substance and essence of the invention, and Without the sacrifice of any of its substantial benefits and advantages. In other words, the invention is not limited and restricted to the precise and exact structural features presented, as these may be varied within wide limits.

I claim:

1. In an appliance of the character described, the combination of an endless backing-belt, means to drive said belt, a l nger endless abradant-belt inclosing and co6perating with said backing-belt, an abutmentwall along the face of which the two belts travel, a stationary form between said belts with which said abradant-belt alone co-acts, means operating lengthwise the backing-belt to tighten it and cause its proper tracking, and means operating transversely of the abradant-belt to cause the tightening and proper tracking thereof, substantially as described.

2. In an appliance of the character described, the combination of an endless backing-belt, means to drive said belt, a longer endless abradant-belt inclosing and cooperating with said backing-belt, an abutmentwall along the face of which the two belts travel, a stationary form between said belts with which said abradant-belt alone co-acts, and means to permit the tightening and secure the proper tracking of said belts, substantially as described.

3. In an appliance of the character described, the combination of an endless backing-belt, means to drive said belt, a longer endless abradant-belt inclosing and cooperating with said backing-belt, an abutmentwall along the face of which the two belts travel, and a stationary form between said belts with which said abradant-belt alone co-acts, substantially as described.

4. In an appliance of the character described, the combination of an endless back ing-belt, means to drive said belt, a longer endless abradant-belt inclosing and cooperating with said backing-belt, an abutmentwall along the face of which the two belts travel, and a form between said belts with which said abradant-belt alone co-acts, substantially as described.

5. In an appliance of the character described, the combination of an endless backing-belt, an endless abradant-belt inclosing and cooperating with said backing-belt, means to drive said belts, means operative lengthwise said backing-belt to tighten the same and cause it to track properly, and means operative transversely of the length of said endless abradant-belt to tighten it and cause it to track properly, substantially as described.

GUSTAVE T. JOHNSON.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

